Conventionally, in the imaging system of a digital camera etc, an image of an object image is formed on an image sensor via a lens and photoelectric conversion of the object image is carried out with this image sensor. An image processing device and image processing method for generating an image signal are known as such.
A plurality of optoelectric transducers are arranged in a matrix form as a single chip-type image sensor. The front face of the sensor is equipped with R (red) G (green) and B (blue) light filters that match with the optoelectric transducers. The image processing device and image processing method apply signal processing to the single color image signals of the output image signal via this light filter to generate a color image.
Hence, the image output via the single chip-type image sensor, is a color mosaic image in which each pixel has only the color data of a single color. In order to generate a color image, it is necessary to provide for each pixel a plurality of color data, such as red (R) green (G) and blue (B).
For this reason, in image processing using a single chip type image sensor, so called demozaic processing (also called color interpolation processing) is performed for each pixel based on the color mosaic image which has the color data of any of the R, G, and B components. Here, demozaic processing is processing in which a color image is generated wherein each pixel has all the color data including the R, G, and B component. Therein color data lacking for a pixel is obtained by carrying out an interpolating calculation of other color data pixels in the pixel circumference (also called color interpolation processing).
For example, the light filter in a single chip type image sensor comprises a Bayer arrangement comprising three colors, R (red) G (green) B (blue) arranged in a matrix form so that in a unit of 4 pixels 1 pixel will result into an R image signal, 2 pixels result into a G image signal and 1 pixel results in a B image signal output via this image sensor. Then, the luminosity of two or more color components is calculated for every pixel from these signals. Methods are known as such wherein an image signal is formed by interpolation (See for example, patent document 1).
In mobile devices, such as a digital camera, when imaging a photographic subject, so called distortion of the image by an inadvertent motion of the digital camera or blur poses a problem. It is known as such to detect motion of a camera with a gyroscope or by digital signal processing of an image and to correct for motion and distortion. For example it is known to move the lens along the optic axis or to correct the pixel positions electronically (See for example patent documents 2).
Patent document 2 describes a correction of the pixel position by parallel translation. However, in order to obtain more nearly high-definition image quality, not only parallel translations but also roll and image deformation caused by yaw and pitch have to be compensated. Moreover it is necessary to have position correction at subpixel level. For position correction at subpixel level, in order to generate a pixel in the position which does not have the proper color information, it is necessary to interpolate the pixel value of the position demanded from a neighborhood pixel (See for example patent document 3).    Patent documents 1: JP,2004-534429,A    Patent documents 2: JP,2006-157568,A    Patent documents 3: JP,2000-298300,A